2.7 Execute disaster recovery plans and procedures
A properly managed tape backups should include the following:
Regular backups according to a pre-determined plan
Verifying the backup tapes for integrity
Labeling tapes properly for easy and unique identification
Storing tapes securely at off-site location
Destroying data on old tapes before disposing off the same
There are primarily three types of backups:
Full backup : Here all the data gets backed up. It usually involves huge amounts of data for large systems, and may take hours to complete. A full backup is preferred instead of incremental or differential backups where it is feasible. However, when there is large amount of data, full backup is done once in a while and incremental or differential backups are done in between. A backup plan is usually put in place prior to taking backup of data.
Differential backup : A differential backup includes all the data that has changed since last full backup. The "differential backup" that was taken earlier (after the "full backup" but before the current "differential backup") becomes redundant. This is because all changed data since last "full backup" gets backed up again.
Incremental backup : It includes all the data changed since last incremental backup. Note that for data restoration the full backup and all incremental backup tapes since last full backup are required. The archive bit is set after each incremental backup. Incremental backup is useful for backing up large amounts of data, as it backs up only the changes files since previous incremental backup.
It is recommended to store the backup tapes in a secure, physically distant location. This would take care of unforeseen disasters like natural disasters, fire, or theft. It is also important that the backup tapes are regularly verified for proper recovery in a test server, even though recovery is not really required at that time. Otherwise, it may so happen that you find a backup tape corrupt when it is really required.
2.8 Exemplify the concepts of confidentiality, integrity and availability (CIA)
Confidentiality: It is important that only approved individuals are able to access important information. It ensures that only authorized parties can view the information. For example credit card numbers.
Integrity: Integrity ensures that the information is correct and no unauthorized person or malicious software has altered the data. In the example of the online purchase, the amount to be transferred should not be altered by any one.
Availability: It ensures that data is accessible to authorized users. The total number of items ordered as the result of an online purchase must be made available to an employee in a warehouse so that the correct items can be shipped to the customer
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